1. Field of the Invention
The present invention relates to an ultrasonic welding apparatus and an ultrasonic welding method, and particularly to the ultrasonic welding apparatus for ultrasonically welding a core wire constructed by bundling plural strands to a terminal clamp, and the ultrasonic welding method.
2. Description of the Related Art
An automobile as a mobile unit is equipped with various electronic devices. In the automobile, a wire harness is cabled in order to transmit, for example, a control signal from a controller or electric power from a power source such as a battery to the electronic devices. The wire harness includes plural electric wires, a terminal clamp attached to a terminal of the electric wires, etc.
Each of the electric wires includes a core wire constructed by bundling plural conductive strands, and an insulating coat part for coating the core wire. The core wire exposed by eliminating the coat part of a terminal of this electric wire is welded to the terminal clamp. The core wire of the electric wire is connected to the terminal clamp using, for example, an ultrasonic welding apparatus (see Patent Reference 1).
For example, an ultrasonic welding apparatus 101 as shown in FIG. 3 is proposed in Patent Reference 1. As shown in FIG. 3, the ultrasonic welding apparatus 101 includes an anvil (not shown) equipped with a terminal clamp 103 including an electrical contact part 131 in which a connection hole 131a connected to a connection terminal disposed in the electronic device is disposed and a core wire weld part 132 which ranges to the electrical contact part 131 and stacks a core wire 121 constructed by bundling plural strands, and a chip 107 opposed to the anvil. Ultrasonic vibration is applied to the chip 107 by a vibrator (not shown). The ultrasonic welding apparatus 101 moves the chip 107 toward the core wire 121 and the core wire weld part 132 (as shown by an arrow). Consequently, the core wire 121 is mutually connected to the terminal clamp 103 by applying ultrasonic vibration in a state of pinching the core wire 121 and the core wire weld part 132 between the chip 107 and the anvil and pressurizing the core wire 121 and the core wire weld part 132 in a direction of approaching each other.
Patent Reference 1: JP-A-2007-305314
However, in the ultrasonic welding apparatus 101 shown in Patent Reference 1 described above, there was fear that a portion of the terminal of the core wire 121 moves (protrudes) to a place overlapping with the electrical contact part 131 in the case of applying ultrasonic vibration in a state of pinching the core wire 121 and the core wire weld part 132 between the chip 107 and the anvil and pressurizing the core wire 121 and the core wire weld part 132 in the direction of approaching each other. As a result of this, in the case of connecting the electronic device to the terminal clamp 103, an operator must screw a nut through a bolt after the connection terminal of the electronic device is stacked on the connection hole 131a of the terminal clamp 103 and a portion of the terminal of the protruding core wire 121 is eliminated so as not to be pinched between the electrical contact part 131 and the head of the bolt, and there was a problem that it takes time to do attachment work for attaching the wire harness to the electronic device. Also, there was a problem of spoiling beauty of the wire harness attached to the electronic device in a state in which the portion of the core wire 121 protrudes thus.